I have 1989 740T with a noisy A/C clutch- not gone, but making "fix me" noises. The car stil uses old freon, so I am going to change over to new coolant gas when i go to work, and add a variable orifice. I see a few things that can be done- some covered in the FAQ- from basic changing the clutch bearing to getting a direct replacement rebuilt to upgrading the compressor to a better type. I read about the need to completely remove all oil from the compressor and system, so this is question #1- if I choose a simple clutch replacement, is it worth the time and effort to drain the old oil out and reuse the compressor? It works fine, btw, just needs coolant- but it is old. And number 2 is about a better compressor- anything that would bolt in that would be an improvement?
Any advice, opinions, caveats?
thanks

R